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ASM Failure Analysis Case Histories: Power Generating Equipment最新文献

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An Unusual Defect in a Superheater Tube 过热器管异常缺陷
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c9001456
{"title":"An Unusual Defect in a Superheater Tube","authors":"","doi":"10.31399/asm.fach.power.c9001456","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c9001456","url":null,"abstract":"\u0000 An unusual type of defect was discovered during hydraulic testing of a water-tube boiler after repairs to the superheater tubes following erosion from soot-blowers. When the pressure reached 700 psi, slight leakage was found to be taking place from one of the superheater tubes in a region where there appeared to be a split, approximately 8 in. long. What was thought to be a split was actually a pronounced fold. Microscopic examination showed that a corrosion-fatigue fissure had developed from one of the inside corners of the fold, presumably as a result of the fluctuating bending stresses to which this portion of the tube would be subjected because of the discontinuity in the tube wall. It was from this fissure that the leakage occurred. It was evident that the defect developed during the manufacture of the tube, probably in the course of a drawing or rolling operation without an internal plug. The diam of this portion of the tube was reduced by local collapse and folding of the section rather than by longitudinal extension of the tube itself.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122581649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cracking in Gas Turbine Blades 燃气轮机叶片开裂
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c0090181
{"title":"Cracking in Gas Turbine Blades","authors":"","doi":"10.31399/asm.fach.power.c0090181","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c0090181","url":null,"abstract":"\u0000 Cracking in gas turbine blades was found to initiate from a mechanism of low-cycle fatigue (LCF). LCF is induced during thermal loading cycles in gas turbines. However, metallography of two cracked blades revealed a change in microstructure at as-cast surfaces for depths up to 0.41 mm (0.016 in.). Evaluation by SEM confirmed the difference in structure was associated with a lack of formation of coarse gamma prime structure in the matrix. Microhardness and miniature tensile test results indicated lower strength consistent with the absence of the coarse gamma prime constituent. The blade vendor found that the lot of hot isostatically pressed (HIP) blade castings had been exposed to an improper atmosphere during the HIP process, resulting in the weakened structure. Because subsequent failures were found in blades that did not come from the suspect HIP lot, the scope of the problem was considered generic, and the conclusion was that the primary failure mechanism was LCF. Material imperfections were a secondary deficiency that had the effect of causing the blades from the bad HIP lot to crack first.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115851085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Failure of a Turbine Vane 涡轮叶片失效
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c0046966
{"title":"Failure of a Turbine Vane","authors":"","doi":"10.31399/asm.fach.power.c0046966","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c0046966","url":null,"abstract":"\u0000 A turbine vane made of cast cobalt-base alloy AMS 5382 (Stellite 31; composition: Co-25.5Cr-10.5Ni-7.5W) was returned from service after an undetermined number of service hours because of crack indications on the airfoil sections. This alloy is cast by the precision investment method. Analysis (visual inspection, 100x/500x metallographic examination of sections etched with a mixture of ferric chloride, hydrochloric acid, and methanol, and bend tests) supported the conclusions that cracking of the airfoil sections was caused by thermal fatigue and was contributed to by low ductility due to age hardening, subsurface oxidation related to intragranular carbides, and high residual tensile macrostresses. No further conclusions could be drawn because of the lack of detailed service history, and no recommendations were made.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116874824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Failure of Copper Alloy 443 Heat-Exchanger Tubes 443铜合金换热器管的失效
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c0048714
{"title":"Failure of Copper Alloy 443 Heat-Exchanger Tubes","authors":"","doi":"10.31399/asm.fach.power.c0048714","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c0048714","url":null,"abstract":"\u0000 Tubes in heat exchangers, made of copper alloy C44300 and used for cooling air failed after 5 to six years of service. Air passed over the shell-side surface of the tubes and was cooled by water flowing through the tubes. Water vapor in the air was condensed (pH 4.5) on the tube surfaces during the cooling process. Air flow over the tubes reversed direction every 585 mm as a result of baffling placed in the heat exchangers. An uneven ridgelike thinning and perforation of the tube wall on the leeward side of the tube was revealed by visual examination. Undercut pits on the outer surface of the tube were revealed by metallographic examination of a cross section of the failed area. Impingement attack which led to perforation was revealed by both the ridgelike appearance of the damaged area and the undercut pitting. The heat exchanger was retubed with tubes made of aluminum bronze (copper alloy C61400).","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126264170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Dezincification of Brass Tubes in a Steam Turbine Condenser 汽轮机凝汽器黄铜管的脱锌
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c9001409
{"title":"Dezincification of Brass Tubes in a Steam Turbine Condenser","authors":"","doi":"10.31399/asm.fach.power.c9001409","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c9001409","url":null,"abstract":"\u0000 Dezincification is a particular form of corrosive attack which may occur in a variety of environments and to which some brasses are susceptible. It is favored by waters having a high oxygen, carbon dioxide, or chloride content, and is accelerated by elevated temperatures and low water velocities. In the present study, steam turbine condenser tubes had to be renewed after 25 years of service. The tubes were nominally of 70:30 brass. The appearance of a typically corroded one showed uniform dezincification attack on the bore, extending from one-half to two-thirds through the tube wall thickness.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115007916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Creep Failure Analysis of Steel Tubes 钢管蠕变失效分析
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c9001711
J. A. Pero-Sanz, D. Plaza, M. Ruiz, J. Asensio, J. Verdeja
{"title":"Creep Failure Analysis of Steel Tubes","authors":"J. A. Pero-Sanz, D. Plaza, M. Ruiz, J. Asensio, J. Verdeja","doi":"10.31399/asm.fach.power.c9001711","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c9001711","url":null,"abstract":"\u0000 Failures of 10Cr-Mo9-10 and X 20Cr-Mo-V12-1 superheated pipes during service in steam power generation plants are described. Through micrographic and fractographic analysis, creep and overheating were identified as the cause of failure. The Larson-Miller parameter is computed, as a function of oxidation thickness, temperature and time, confirming the creep failure diagnostic.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128460894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Stress-Corrosion Cracking of a Brass Tube in a Generator Air Cooler Unit 发电机空冷机组黄铜管应力腐蚀开裂
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c0091703
{"title":"Stress-Corrosion Cracking of a Brass Tube in a Generator Air Cooler Unit","authors":"","doi":"10.31399/asm.fach.power.c0091703","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c0091703","url":null,"abstract":"\u0000 An arsenical admiralty brass (UNS C44300) finned tube in a generator air cooler unit at a hydroelectric power station failed. The unit had been in operation for approximately 49,000 h. The cooling medium for the tubes was water from a river. Air flowed over the finned exterior of the tubes, while water circulated through the tubes. Investigation (visual inspection, leak testing, history review, 100X micrographs etched in potassium dichromate, chemical analysis, and EDS and XRD analysis of internal tube deposits) supported the conclusion that the cause of the tube leaks was ammonia-induced SCC. Because the cracks initiated on the inside surfaces of the tubes and because the river water was not treated before it entered the coolers, the ammonia was likely present in the river water and probably concentrated under the internal deposits. Recommendations included either eliminating the ammonia (prohibitively expensive in cost and time) or using an alternate material (such as a 70Cu-30Ni alloy or a more expensive titanium alloy) that is resistant to ammonia corrosion as well as to chlorides and sulfur species.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129898034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Recovery of a Type 304 Stainless Steel Piping System Contaminated with Chlorides 被氯化物污染的304型不锈钢管道系统的回收
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c9001559
A. A. Stein, V. Zilberstein, W. S. Clancy, G. J. Davis
{"title":"Recovery of a Type 304 Stainless Steel Piping System Contaminated with Chlorides","authors":"A. A. Stein, V. Zilberstein, W. S. Clancy, G. J. Davis","doi":"10.31399/asm.fach.power.c9001559","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c9001559","url":null,"abstract":"\u0000 One inch diam Type 304 stainless steel piping was designed to carry containment atmosphere samples to an analyzer to monitor hydrogen and oxygen levels during operational and the design basis accident conditions that are postulated to occur in a boiling water reactor. Only one of six lines in the system had thru-wall cracks. Shallow incipient cracks were detected at the lowest elevations of one other line. The balance of the system had no signs of SCC attack. Chlorides and corrosion deposits in varying amounts were found throughout the system. The failure mechanism was transgranular, chloride, stress-corrosion cracking. Replacement decisions were based on the presence of SCC attack or heavy corrosion deposits indicative of extended exposure time to chloride-contaminated water. The existing uncracked pipe, about 75 percent of the piping in the system, was retained despite the presence of low level surface chlorides. Controls were implemented to insure that temperatures are kept below 150 deg F, or, walls of the pipe are moisture-free or the cumulative wetted period will never exceed 30 h.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130412273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Aging of Boiler Rivets 锅炉铆钉老化
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c9001448
{"title":"Aging of Boiler Rivets","authors":"","doi":"10.31399/asm.fach.power.c9001448","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c9001448","url":null,"abstract":"\u0000 Rivets from the longitudinal seam of the terminal shell ring of a 12 year old Lancashire boiler broke off easily during examination. Cleavage fractures indicated a brittle material. Microstructure of a sectioned rivet head was typical of a normal rimming steel except the ferrite crystals contained numerous nitride needles. Their existence indicated an abnormally high nitrogen content. If such a steel is heated for a lengthy period to a temperature of that prevailing in a boiler, precipitation of the nitrides may be expected, with consequent embrittlement. In this case, embrittlement of this type was the primary cause of the breaking off of the type rivet heads. Nothing was observed in the course of the examination that suggested caustic cracking.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133503530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Stress-Corrosion Cracking of Inconel X-750 Springs Inconel X-750弹簧的应力腐蚀开裂
ASM Failure Analysis Case Histories: Power Generating Equipment Pub Date : 2019-06-01 DOI: 10.31399/asm.fach.power.c0048158
{"title":"Stress-Corrosion Cracking of Inconel X-750 Springs","authors":"","doi":"10.31399/asm.fach.power.c0048158","DOIUrl":"https://doi.org/10.31399/asm.fach.power.c0048158","url":null,"abstract":"\u0000 Several of the springs, made of 1.1 mm diam Inconel X-750 wire and used for tightening the interstage packing ring in a high-pressure turbine, were found broken after approximately seven years of operation. Intergranular cracks about 1.3 mm in depth and oriented at an angle of 45 deg to the axis of the wire were revealed by metallographic examination. A light-gray phase, which had the appearance of liquid-metal corrosion, was observed to have penetrated the grains on the fracture surfaces. The spring wires were found to fracture in a brittle manner characteristic of fracture from torsional loading (along a plane 45 deg to the wire axis). Liquid-metal embrittlement was expected to have been caused by metals (Sn, Zn, Pb) which melt much below maximum service temperature of the turbine. The springs were concluded to have fractured by intergranular stress-corrosion cracking promoted by the action of liquid zinc and tin in combination with static and torsional stresses on the spring wire. As a corrective measure, Na, Sn, and Zn which were present in pigmented oil used as a lubricant during spring winding was cleaned thoroughly by the spring manufacturer before shipment to remove all contaminants.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133724555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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